Boiler leaking

Discussion in 'Shop Talk' started by mistletoad, Oct 16, 2006.

  1. mistletoad

    mistletoad Well-Known Member Supporter

    Messages:
    4,283
    Joined:
    Apr 16, 2003
    Location:
    Southern Maryland
    No, not the water heater, this time we have problems with one of the propane boilers than feeds the baseboard heaters. Water was leaking out of the overflow pipe at a rate of about 1 gal per hour (we didn't notice until we had a nice flood going). The heat was not on. I have cut the electric and the water supply to the boiler, but does anyone one know what might have gone wrong here?
     
  2. moopups

    moopups In Remembrance

    Messages:
    7,102
    Joined:
    May 12, 2002
    Location:
    In beautiful downtown Sticks, near Belleview, Fl.
    Hard water minerals and/or calcium deposits can fault the pressure valve, start there.
     

  3. mistletoad

    mistletoad Well-Known Member Supporter

    Messages:
    4,283
    Joined:
    Apr 16, 2003
    Location:
    Southern Maryland
    Thx Moopups, the pressure valve releases ok - I opened that to make sure the drip stopped - is that all I need to check on that?
     
  4. ninny

    ninny Well-Known Member

    Messages:
    4,341
    Joined:
    Dec 12, 2005
    Location:
    Corpus Christi, Texas
    If you haven't done anything to increase the water pressure that might be causing the valve to open, it's likely that you have a bad valve. They're not that expensive. I'd replace the thing. Check the tag on top of the valve for the temp/pressure that the valve operates at and get one with a similar rating.
     
  5. mistletoad

    mistletoad Well-Known Member Supporter

    Messages:
    4,283
    Joined:
    Apr 16, 2003
    Location:
    Southern Maryland
    Oh, I am so stupid sometimes - from your post it now (and only now) occurs to me that water will only come out of that particular pipe if the pressure relief valve is open for whatever reason. So, if I can think out loud here, if the prv doesn't close properly, the system could leak even if the pressure is normal. Do I have that right? I was thinking in terms of it not opening, rather than perhaps not closing. Thank you so much.
     
  6. ninny

    ninny Well-Known Member

    Messages:
    4,341
    Joined:
    Dec 12, 2005
    Location:
    Corpus Christi, Texas
    You've got it right. The valve can leak if the water pressure is normal. It's just spring pressure that keeps the valve closed and the spring can get weak. I'd pop the valve handle a couple of times and see if the valve will re-seat. If it continues to leak and the water pressure/temp are both normal, replace the valve. Like I said, get the info off the tag on the valve and replace it with a similar type. If you decide to replace it, another option would be to turn the water off to the boiler, unscrew the valve and take it with you to a plumbing supply outlet. They can get you one similar. Good luck...
     
  7. BD

    BD Active Member

    Messages:
    34
    Joined:
    Jul 23, 2005
    hi, before you change out relief valve check the reading on pressure gauge. Full heat could be around 12 to 20 pounds. If gauge is higher and causing the 30 pound relief valve to drip you may have a water logged expansion tank which means it is all water and no air cushion in it OR the city make up pressure reducing valve may be allowing water into system. This is normally set at 12 pounds.BOB
     
  8. morrowsmowers

    morrowsmowers Well-Known Member

    Messages:
    1,096
    Joined:
    Jun 14, 2004
    Location:
    NJ
    Do you have an auto fill on the system??? If that was constantly passing line pressure into the hydronic system it would be higher than the safety valve setting and would cause your same problem. Unless your system is leaking you should be able to fill it and close the valve. If it stops leaking with the valve closed then check the auto fill if you have one -- if not leave the valve to the cold water closed.

    Ken in Glassboro, NJ :)
     
  9. Ross

    Ross Moderator Staff Member Supporter

    Messages:
    13,086
    Joined:
    May 9, 2002
    Location:
    Ontario
    The makeup valve is what I was thinking too, over pressuring the cold boiler system. That needs checking too and replace the T+P valve anyhow with the exact rated replacement valve (sorry ninny perhaps thats what you meant) they're too cheap to trust with old age or erratic performance.